<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>成绩</title>
</head>

<body>
	<script language="javascript">
		
		var r=5;
		var pai=(3.14*100)/100;
		s=pai*r*r;
		c=2*pai*r;
		//document.write('圆的周长：'+c+'<br>'+'圆的面积：'+s);
		
		//var r = window.prompt("请输入成绩(0~100)"," ");
		if(r>=90)
			document.write('优秀');
		else if(r>=80&&r<90)
			document.write('良好');
		else if(r>=70&&r<80)
			document.write('中等');
		else if(r>=60&&r<70)
			document.write('及格');
		else if(r<60)
			document.write('不及格');
		
	</script>
</body>
</html>